This invention relates to apparatus and method for positioning a web roll upon a belt letoff and the like, and is an improvement upon apparatus illustrated in U.S. Pat. No. 5,209,418.
A web roll may be placed upon a tilted table for gravity feeding the web roll upon a cradle formed by a driven belt carried between a pair of parallel horizontal rolls mounted for rotation upon a fixed frame wherein one of the rolls is pivoted downwardly to lower one side of the cradle for receiving the web roll preparatory to unwinding. While letoffs constructed in accordance with the aforesaid patent are useful in unwinding web rolls usually consisting of cloth, it is desirable to provide an apparatus and method for centering the web roll for placement upon a table for gravity feeding same upon the belt and thence within the cradle of a belt letoff.
Web rolls utilized in the textile industry are extremely large, heavy and difficult to manipulate. The prior art contemplates the delivery of the web rolls as upon lift trucks for deposit upon a tilted table for feeding and delivering same to the belt of a belt letoff. The proper centering of these rolls is usually done by trial and error requiring considerable manual manipulation often resulting in inaccuracies in centering the rolls upon the belt letoff. The invention hereof contemplates apparatus and method including a pair of spaced detectors for centering the web roll through the use of apparatus for simultaneously moving the pair of detectors in or out together. The invention further contemplates the use of a driven conveyor which is manipulated responsive to signals from the detectors preparatory to actuation of tilt mechanism for lifting the web roll thus centered upon the cradle of the belt letoff.
While the invention is described herein in connection with the centering of a web roll for use in unwinding utilizing a belt letoff, other uses of the invention may be undertaken wherein it is desirable to center a web roll as upon a winding or dewinding apparatus for further manipulation of the web.